kicad-developers team mailing list archive

["�vind Aabling" <Oyvind.Aabling@xxxxxxxx>]

On Tue, 24 Aug 2010, Alex G wrote:

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> First of all, sorry for the latent reply. I've been in a no-internet
> zone for the last week or so (and even then, without my linux box, there
> wasn't much I could do
>
> > The datasheet doesn't include recommended footprints,
> > but they'll be similar to the DFNs I've already defined.
>
> There are named "land patterns" on maxim's website:
> http://www.maxim-ic.com/design/packaging/index.mvp?a=2&f=

Yes, there are both land patterns and package outlines,
but there's an awful lot of them to go through ...

> > > There's one thing that puzzles me - the Maxim datasheet lists two
> > > versions of the package for N=8 and three each for N=10 and 14,
> > > but unless I'm blind, all variants have identical dimensions ?
> There are a few duplicates, but there are some 3x3mm TDFN packages and
> some 2x2mm packages.

I've looked at some of the datasheets above, and I think the datasheet
http://pdfserv.maxim-ic.com/package_dwgs/21-0137.PDF is wrong
- the difference between the variants seems to be the size of
the exposed pad (D2,E2), but 21-0137.PDF lists them as identical.

> Actually, way more than I originally thought:
>
> TDFN 8 2x2mm
> http://pdfserv.maxim-ic.com/package_dwgs/21-0168.PDF
> http://pdfserv.maxim-ic.com/land_patterns/90-0064.PDF
>
> TDFN 10 3x2mm
> http://pdfserv.maxim-ic.com/package_dwgs/21-0429.PDF
> http://pdfserv.maxim-ic.com/land_patterns/90-0082.PDF
>
> TDFN 8 2x3mm
> http://pdfserv.maxim-ic.com/package_dwgs/21-0174.PDF
> http://pdfserv.maxim-ic.com/land_patterns/90-0091.PDF
>
> UTDFN 6 2x2mm:
> http://pdfserv.maxim-ic.com/package_dwgs/21-0490.PDF
> http://pdfserv.maxim-ic.com/land_patterns/90-0344.PDF
>
> An interesting pattern for TDFN 8 2x2 with spacing information:
> http://pdfserv.maxim-ic.com/land_patterns/90-0349.PDF
>
> I think there are also larger packages as well;
>
> TDFN 14L 3x5mm:
> http://pdfserv.maxim-ic.com/package_dwgs/21-0253.PDF
> http://pdfserv.maxim-ic.com/land_patterns/90-0246.PDF
>
> TDFN 10L 3x4mm
> http://pdfserv.maxim-ic.com/package_dwgs/21-0268.PDF
> http://pdfserv.maxim-ic.com/land_patterns/90-0247.PDF

Yes, much larger - up to 56 "pins" :-)

> Anyway, way too much information for the moment. I'll check the updated
> qfn board, and compare that to the footprints I drew.
>
> What do you want to do about the molex connectors? If I had the
> generator script, I could play around with it and see if I can get some
> work done on the connectors. It could also be of great help if we could
> convert IGES to VRML automatically. Worst case, I'd have to manually do
> it for 100+ connectors

I've taken a quick look at the IGES file format, and
it's fortunately not binary, but (sort of) human readable
ASCII (in good ol' punched-card 80-colums fixed format :-)

There's a Wiki page on IGES: http://en.wikipedia.org/wiki/IGES,
but it doesn't go into enough detail to be _really_
useful (some of the info is there, but not all).

I haven't understood what all the numbers and fields means yet, but
as freecad can read IGES (*), the freecad source should also contain
some useful info for writing a script to convert IGES to VRML.

(*): Well, sort of - freecad is definitely alpha code:
I've tried feeding the simple example on the Wiki to freecad,
and it gets the coloring wrong - the points, arcs and lines
should be yellow, red and green, but they're all shown in black.
Also, Wiki Ref 6: http://www.wiz-worx.com/iges5x/wysiwyg/f214x.shtml
is totally wrong (most of it is missing).
Fortunately, the missing stuff is 2D graphics, and the Molex
connectors shows up just fine (except for the coloring).

As KiCad only understands VRML IndexedFaceSet and materials,
any 1D and 2D info (points, lines, arcs, etc.) in an IGES
file will get lost - only the 3D faces can be converted.
However, that should be enough for kicad, I think.

> Alex G,
>
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Øyvind.

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